Anyone witnessing a rocket launch will be struck by the noise levels, even when observing from several kilometres away. A satellite on top of its launcher is exposed to much higher levels, of course. So testing is essential to ensure that the satellite structure can withstand such a sustained loud sound.

This first Galileo Full Operational Capability (FOC) satellite, successor to the four Galileo navigation satellites already in orbit, underwent acoustic testing in July, part of a full-scale test campaign taking place at ESA’s ESTEC Test Centre in Noordwijk, the Netherlands.

The satellite was placed in the Large European Acoustic Facility, LEAF, effectively the largest sound system in Europe. A quartet of noise horns are embedded in one wall of this 11 m wide by 9 m deep and 16.4 m high test chamber.

Noise is generated by passing a carefully modulated flow of gaseous nitrogen through the horns, following the predetermined test profile – this inert gas selected to avoid any contamination of any delicate onboard systems, the satellite having been placed in flight configuration for the purpose of the test [...]